mk3 build thread

[B-chi]

@ Ian. What I've found from my own experience, research, etc is that cable termination comes down to preference.

A well crimped connection is better than a badly soldered one.

A well soldered connection is better than a badly crimped one.

Other than that 'all is fair'. I've heard/read argumens for both sides & they both seem valid.

The standard cabling that I replaced was crimped not soldered.

My cable is currently from a nuclear research facility, so is not cheap (well it was for me lol), it was crimped with proper crimpers made to be able to crimp that size cable. All it needs is heat shrink round it & I think it should be fine.

Just read that back to myself & it seems a bit arrogant. It's not meantto be, I hear what people are saying but I've decided that there is enough evidence to justify what I've done.

If I was going for an out & out spl or sq system then I would spend more time & money investigating, but as it's a daily/Ltd competition use I reackon/hope it should be fine.

I do appreciate all the comments/criticisms/suggestions that have been made, that's how we learn/get better at things.

On a side note is anyone able to sort that link out for my sub box. I'm on the iPhone & I can't for the life of me get it to f**kIng work, bloody thing!

I've got a comp tomorrow so will post up my scores & comments on tomorrows activities!

[ianw3321]

Hi sorry if I came across as arrogant I was only trying to be helpfull perhaps you should read this.  http://cs.pennnet.com/display_article/194291/42/ARTCL/none/none/1/Electrical-connections:-What-you-can-do-to-prevent-corrosion/

[B-chi]

No don't be silly Ian. I'll give that a read later. Went to T17 yesterday @ my single 12inch with 1100w mnaged 142db @ 34hz. Well chuffed. I also came 2nd in 120-129.9 bassrace.

[ianw3321]

I said earlier on that I was inexperienced with car audio but highly experienced with home audio. having said that I have experemented in the past with in my opinion poor results and being content with a "mediocre" stereo in my car. My main problem is power, you talk about many hundreds of watts and I have heard others and seen specs with similar power rating, but its the 12v and ohms law that gets me. My amp in my home puts out a modest 80w rms per chanel into an 8 ohm load, but its input voltage is 80v to develop that. In a car you are resticted to 12v. I know they try to get round this problem to a certain extent by using low impedance drive units, usually four ohms but never the less. Power (watts) equals volts x amps, ok we know the maximum output voltage of a car amp is about 10v once the dreaded voltage drop has been accounted for. All we need is the amperage to determine the maximum power that an amp can deliver into a fixed load. Lets make this fixed load really low(2 ohms) and work out the amps and finally the rms. Ok to work out the amps we use ohms law which states I=V divded by R or current = volts divided by resistance, we know  the output voltage is ten and the resistance is 2 ohms so 10 devided by two is 5 or 5 amps, and power = volts times amps which gives us a maximum power output of 50watts into a 2 ohm load around half that into a 4 ohm load and half again into an 8 ohm load, so quite where these multi hundred watt power figures come from I am at a loss to understand. Perhaps your self bi-chi or someone else can explain. Has anyone experemented with higher voltage supplies and amps?

[B-chi]

My amp, with engine on sees 14.1v (got a voltmeter). The amp in question is a classD 1100wrms mono amp. It has 4x 25a fuses. The 1100w stated will only be delivered when the amp is at full whack & seeing 14.4v so with it seeing 14.1v the output will drop to maybe 1000-1050wrms. (figure is a complete guess).

Aren't home audio systems resticted to 16a?

Car audio (12v), is restricted to the output voltage of the alternator but the amount of amps you can use is unlimited. I know guys with over 1000ah of battery power.

Some people do run 2 seperate alts. A standard 14.4v for car & in some cases 18v for audio.

A guy at the show I went to on Saturday was running 12,000wrms (2/3rds of his power ATM) that's a lot of batteries.   

[ianw3321]

First your point about hi fi amps being restricted to 16A, no the current is only restricted by the power supply for the amp and the output transistors. You say your amps current output is unrestricted but it is as  I mentioned by the amps output stage but the point I was making is that the load (or speaker) determines the amount of current used (ohms law) and at 4 ohms it aint much you would need to connect loads of speakers in parrallel to utalise all that current. I suppose the small area of air in a car (one step up from ear phones) means you dont need a lot of power as 12v 14v is neither hear nor there you need 100v for real power.

[B-chi]

My amp is running at 1 ohm. My sub is dual 2 ohm so gives the amp a 1 ohm load.

I'm not quite following why you need loads of voltage to get loud.

Mine is loud enough to make the boot move half inch. My car stereo has always been louder than my home audio!

[ianw3321]

voltage is power amps go distorted when the voltage limit is reached (clipping) as I mentioned earlier it is only in the confines of your car that it will be loud, in a bigger space it would be a bit lost.

[B-chi]

For some reason I locked the thread. Not sure why or how but finally got my laptop back.

So heres the pic of my sub box.